Yes, sorry for the hijack. It was just an out-of-the-blue idea which popped in my head in reaction to Schooner's post.
And yes, I meant that commit. I remember from my LinuxCNC days that CPU hogging, as you aptly named, used be the thing. (Not so sure now as I don't follow that project closely, only the forum.) And I quite liked the multicore, multi-instance granularity of Machinekit. However, isolating one(/more) CPU core for the special process of software step generation doesn't seem so bad. Zultron tested it on J1900 (I think) which is board everybody is composing odes about (at least on LinuxCNC forum) but it's little old and harder to get. So it would be interesting to try it on J5005 or J40-something based boards, which are around 100 euros. Cern. Dne čtvrtek 28. února 2019 19:43:34 UTC+1 Bas de Bruijn napsal(a): > > So as not to hijack the thread, a new thread > > On 28 Feb 2019, at 19:20, [email protected] wrote: > > BTW, did someone else (than Zultron) try to use the core isolation feature > to "turn on" back the step signal generation in software? My electrotrash > which I use for Machinekitdoes not have cores to spare. > > > Yes, you’re probably referring to this? > https://github.com/machinekit/machinekit/pull/1426 > > Although i dont use software step generation. The latency obtained is very > good (6-7 us). > > What was done here is to force the thread to run on designated cpu’s. > Because these cpu’s were isolated during startup (isolcpus= kernel > parameter) there are no other processes running on these cpu’s. > These cpu’s must be the pair that share their L2 cache, or hyperthreading > should be disabled and that cpu used. > > A setup that was historically used with iolcpus= kernel parameters was to > run everything on 1 cpu (disabling all but one), so that the cpu was hogged > and that got good latency results. > > This cgroups setup is the other way around, you’ll only run HAL on the > isolated cpu’s, the /RT cpuset. > > I’m no expert on this so there might be some more clarification needed > from the experts :) > > Bas > -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. Visit this group at https://groups.google.com/group/machinekit. For more options, visit https://groups.google.com/d/optout.
